This invention relates to carpenter's, mason's, pipe fitter's and other mechanic's levels, measuring devices and squares, and more particularly to levels which are adjustable in length, can measure inside dimensions and can extend to large collapsible squares. Different tasks of carpentry work requires differing lengths of levels and squares depending upon the particular project. Accordingly, levels come in many various lengths, as do carpenter's squares. A leveling device or square of a suitable and convenient length for a particular job and yet manageable in transporting and storing is very desirable. Further, a single extendable level which can meet the requirements of several individual levels is even more desirable. Finally, a single extensive level which can fit into a standard tool box, yet can meet the needs of several different length levels, as well as several tools is most desirable. Many efforts have been made to create expandable levels and collapsible squares in many configurations.